ASP data type problem

[Spork52]

I am retrieving two numeric values from a SQL Server table (both have precision 7 and scale 2) and then attempting subtraction with vbScript. Keep getting the "Type Mismatch" error. When I test the data types with vartype and typename functions I get vartype = 14 for both (which I thought meant decimal), but typename give me this

Microsoft VBScript runtime error '800a01ca'
Variable uses an Automation type not supported in VBScript: 'TypeName'

If I apply CStr or CDbl to both values then subtraction works.

What's going on here? What is the data type and why do I have to coerce the data types before subtraction?

 

[tsuji]

For numeric accuracy, db's usually support more data type than vbscript is prepared to support. vt_decimal is one of those. It is not hopeless for vb-scripter: it can still hold the data vt_decimal included, only you have to convert it to double or float or currency before doing arithmetic with it. Here is a summing up by the insider.

http://blogs.msdn.com/ericlippert/archive/2004/07/14/183241.aspx